Novel Plant Cysteine Protease Has a Dual Function as a Regulator of 1-Aminocyclopropane-1-Carboxylic Acid Synthase Gene Expression

• Published in: The Plant cell 2005-04, Vol.17 (4), p.1205-1216
• Main Authors: Matarasso, Noa, Schuster, Silvia, Avni, Adi
• Format: Article
• Language: English
• Subjects: 1-aminocyclopropane-1-carboxylate synthase; Acs2 gene; Active Transport, Cell Nucleus - physiology; beta-glucuronidase; binding capacity; binding proteins; Biosynthesis; Carboxylic acids; Cysteine Endopeptidases - genetics; Cysteine Endopeptidases - isolation & purification; Cysteine Endopeptidases - metabolism; cysteine proteinases; DNA; DNA, Complementary - analysis; DNA, Complementary - genetics; endo-1,4-beta-xylanase; Enzymatic activity; Enzymes; ethylene inducing xylanase; gene expression; Gene expression regulation; Gene Expression Regulation, Enzymologic - physiology; Gene Expression Regulation, Plant - physiology; Genes; Leaves; Lyases - genetics; Lyases - isolation & purification; Lyases - metabolism; Lycopersicon esculentum - enzymology; Lycopersicon esculentum - genetics; Molecular Sequence Data; Nicotiana tabacum; nucleotide sequences; Plant cells; Plant growth; Plant Proteins - genetics; Plant Proteins - isolation & purification; Plant Proteins - metabolism; Plants; Plants, Genetically Modified - enzymology; Plants, Genetically Modified - genetics; promoter regions; Promoter Regions, Genetic - genetics; Protein Binding - physiology; Reporter genes; Response Elements - genetics; Sequence Homology, Amino Acid; Sequence Homology, Nucleic Acid; small ubiquitin-related modifier protein; Solanum lycopersicum var. lycopersicum; tobacco; Tomatoes; transcription (genetics); transcription factors; Transcription Factors - genetics; Transcription Factors - isolation & purification; Transcription Factors - metabolism; Transgenic plants; Yeasts
• ISSN: 1040-4651; 1532-298X; 1532-298X
• DOI: 10.1105/tpc.105.030775

The hormone ethylene influences plant growth, development, and some defense responses. The fungal elicitor Ethylene-Inducing Xylanase (EIX) elicits ethylene biosynthesis in tomato (Lycopersicon esculentum) and tobacco (Nicotiana tabacum) leaves by induction of 1-aminocyclopropane-1-caboxylic acid synthase (Acs) gene expression. A minimal promoter element in the LeAcs2 gene required for EIX responsiveness was defined by deletion analysis in transgenic tomato plants. The sequence between -715 and -675 of the tomato Acs2 gene was found to be essential for induction by EIX. A Cys protease (LeCp) was isolated that specifically binds to this cis element in vitro. Ectopic expression of LeCp in tomato leaves induced the expression of Acs2. Moreover, chromatin immunoprecipitation showed that LeCp binds in vivo to the Acs promoter. We propose a mechanism for the dual function of the LeCp protein. The protease acts enzymatically in the cytoplasm. Then, upon signaling, a small ubiquitin-related modifier protein binds to it, enabling entrance into the nucleus, where it acts as a transcription factor. Thus, LeCp can be considered a dual-function protein, having enzymatic activity and, upon elicitor signaling, exhibiting transcriptional factor activity that induces LeAcs2 expression.